Antenna Feed Circuit With Cascade Phase Shifters for Wideband Loss Control
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Solution Overview
Problem
Existing power feeding circuits and phase shift circuits in antenna systems suffer from significant loss of passing power, especially when phase-shifting signals for multiple frequency bands, leading to narrowed bandwidth and reduced antenna gain.
Innovation Solution
The proposed solution involves a circuit board with a phase circuit portion that phase-shifts input signals in an opposite direction to adjacent signals, using a cascade-type phase shifter with multiple single-type phase shifters connected in series, to minimize power loss across a wide frequency band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-type phase shifter performs large phase shift (e.g., 180 degrees), then the phase difference between signals is corrected, but the loss of passing power increases significantly
Solution Approach 1:
The phase shifter is divided into multiple single-type phase shifters connected in series, each performing a smaller phase shift. For example, instead of one phase shifter performing 180 degrees, multiple phase shifters each perform 30-60 degrees, accumulating to the required total phase shift while reducing power loss at each stage.
Solution Approach 2:
The patent makes the phase shift amount adjustable by changing the number of active phase shifters in the cascade chain. This allows optimization between phase accuracy and power loss depending on the operating conditions and frequency band being used.
2Adaptability or versatility
If phase shift amount increases to cover wide frequency bands, then multi-band reception capability is improved, but the bandwidth is narrowed due to amplitude attenuation
Solution Approach 1:
By segmenting the phase shift function into multiple smaller stages, each stage operates within a frequency range where power loss is minimal. The cascade structure allows the system to maintain acceptable power levels across a wider overall frequency band than a single large phase shift could achieve.
Solution Approach 2:
The patent changes the phase shift parameter distribution across multiple stages rather than concentrating it in one stage. This parameter redistribution allows the system to achieve the same total phase shift while operating in a frequency range where each individual stage experiences less attenuation, thereby expanding the usable bandwidth.
3Loss of energy
If cascade-type phase shifters with multiple stages are used, then power loss is suppressed across wide frequency band, but the device complexity increases
Solution Approach 1:
Multiple single-type phase shifters are merged into a single cascade chain, sharing common signal paths and power supplies. This combining approach reduces the overall complexity compared to having separate phase shift circuits for each function, while still achieving the power loss suppression benefits of multiple stages.
Solution Approach 2:
The cascade-type phase shifter structure serves multiple functions simultaneously: it provides the required phase shift, suppresses power loss across wide frequency bands, and enables adjustable phase shift amounts. This multi-functionality reduces the need for additional separate circuits, thereby managing complexity.
Data Source
AI summary
Provided is an antenna that suppresses increase in passing loss when phase-shifting signals input from an antenna element throughout a wide frequency band. The antenna includes a power feeding circuit 20 that converts four input signals input with phase differences different by 90 degrees from an antenna element so that the four input signals have a same phase and outputs them as one combined signal from an output terminal s31. The power feeding circuit 20 includes a first phase circuit portion 200A that phase-shifts the four input signals and combines them two by two to output two first combined signals, and a second phase circuit portion 200B that phase-shifts each of the two first combined signals by 90 degrees by reversing a shift direction to combine the two first combined signals. The second phase circuit portion 200B includes cascade-type phase shifters 241, 242 in which two 45 degrees phase-shifters or three 30 degrees phase shifters are connected in series.